Weil divisors on rational normal scrolls (Q2717173)

Let \(X\subset\mathbb{P}^n\) be a singular \(r\)-dimensional rational normal scroll. Hence \(\deg(X)= n-r+1\) and \(X\) is a cone with vertex \(\text{Sing} (X)\). Here the author study Weil divisors on \(X\) stressing the difficult case \(\dim(\text{Sing} (X))=-r-2\). In this case she computes the intersection numbers of \(r\) divisors. In this case all effective divisors and (if \(r\geq 3)\) all complete intersections of two effective divisors are arithmetically Cohen-Macaulay.NEWLINENEWLINEFor the entire collection see [Zbl 0960.00042].